1. Field of the Invention
The present application relates generally to locomotives and, more particularly, to a brake system for use with a pneumatic brake system on a train.
2. Description of Related Art
Locomotives have been used for many years as a means of transporting people and cargo. Due to the significant loads locomotives haul, the time and distance it takes to attain a desired level of speed and to ultimately decrease speed is rather large when compared to motorized vehicles. Improvements in braking systems have been needed for some time.
For example, currently air brakes are used in freight trains. Such braking systems create a delay in being applied evenly throughout the train. A single pneumatic valve is typically located on the forward locomotive. When brakes are to be applied, a brake signal opens the pneumatic valve to release air pressure within the brake pipe. This causes a pulse wave through the brake pipe where an non-uniform pressure drop occurs within the brake pipe. Brakes are applied sequentially from car to car along the train as the pulse wave (signal) moves through the train's brake pipe. A time delay occurs from the signal reception and resultant braking in the first car to the signal reception and resultant braking in the last car. This causes an uneven application of brakes resulting in increased stopping distances and the creation of in-train forces and stresses.
A device occasionally used to try and improve the design are electronically controlled pneumatic (ECP) brakes. Such systems are typically designed to incorporate electronic controls that replace the existing pneumatic operation of each brake with an electronically operated brake. For example, the pneumatic system is replaced by an electronically controlled system where electronic valves actuate a piston to apply brakes. Pressurized air within the brake pipe is used primarily to replenish the air cylinder used to operate the piston.
ECP brake systems generally interfere with existing pneumatic brake systems. Modifications are required to the pneumatic systems to incorporate the ECP brake systems. The modifications prevent ECP brake system cars from operating interchangeably with cars utilizing solely pneumatic brake systems. A disadvantage of the ECP system is the need for it to be applied to each car to ensure a consistent and even braking since the existing air brake system is modified. This therefore decreases the interchangeability of rail cars between trains of different braking systems. Also, costs and weight increase when each train car is required to need braking modifications.
A more interchangeable and cost effective braking system is needed. Although great strides have been made in braking systems, considerable shortcomings remain.
While the system and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the application to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims.